same issue as mine!!! i downloaded the firmware 5 times for my L520 but still don’t solve the problem! NSU, NSRT, NCS, Nokia data package manager, product support tool for store always gives me an error “Data package firmware corrupted”, i used Navifirm+, Nokia data package manager, NSU, SCS, NSRT, and i even download firmware from a site but none of them solved my problem!